They were two of the most traumatic episodes of the 80s, but until this year, few made a connection between the "battle of Orgreave" in 1984 and the Hillsborough disaster five years later, also overseen by South Yorkshire police, in which 96 Liverpool supporters died.

Now, pressure is building for an investigation into South Yorkshire police's conduct at and following Orgreave, when South Yorkshire police evidence collapsed and 95 striking miners were acquitted of serious criminal charges.

In 1985, it emerged at the first trial of 15 miners, for riot and unlawful assembly, that police officers had significant parts of their statements, giving evidence of general disorder by miners, dictated to them by another officer.

The prosecution withdrew following analysis by a Home Office handwriting expert that a police officer's signature on a statement of evidence against one of the accused miners, Bryan Moreland, had not been written by that officer.

South Yorkshire county council's police committee stated its concern at the time that the allegations of officers having their statements dictated and the signature forged "amounted to inaccurate, perjured evidence at the very least, and called into credibility … the chief constable".

Wright did not accept any fault at all in the Orgreave operation and prosecutions. But he acknowledged unapologetically that there was a deliberate effort to convict miners of riot and unlawful assembly, which carried potentially long, even life, prison sentences. In a report to the police committee dated 25 September 1985, Wright set out the details of the operation to deal, he said, with escalating violence in picketing at the Orgreave coking plant, which miners have always argued was exaggerated.

"The chief constable decided that the usual charge of disorderly conduct, contrary to the Public Order Act, was inadequate and that, where appropriate, charges of unlawful assembly and riot should be preferred," Wright wrote in his report.

He set up a dedicated unit to target the miners: "A chief superintendent well experienced in CID work was appointed and directed by the chief constable to organise the collection and collation of evidence, and the preparation of prosecution files whenever the scale and nature of events at Orgreave so required."

On 18 June 1984, the day of the most notorious confrontation, when police were filmed attacking miners then claimed they were attacked first, Wright recorded: "The evidence-gathering team comprised one detective inspector, one detective sergeant, and four detective constables." It has never been revealed who these officers or the more senior commanding officers were, nor if any were then involved in what has been labelled the black propaganda unit which conducted the campaign to falsely blame the Liverpool supporters for the Hillsborough disaster.

Not a single conviction was secured for riot or unlawful assembly in three separate trials of 124 miners, Wright acknowledged, but in the second, 19 men agreed to be bound over to keep the peace.

In his report, Wright did not address at all the revelation in court that officers had statements dictated to them, the allegation that the police signature was forged, nor the defence lawyers' overall claim that the evidence against the miners had been fabricated. Wright argued that the evidence at the main Orgreave trial was inadequate solely because of the "lapse of time" between the events and the trial.

In 1991, South Yorkshire police made the biggest-ever police payout for a civil action, £425,000, to 39 miners suing over the actions at Orgreave and prosecutions. Yet no officer was ever disciplined, no reform of the force took place, there was no public inquiry after Orgreave, as called for by several Labour MPs.

Four years after the collapsed trial, South Yorkshire police mismanaged the FA Cup semi-final at Hillsborough, then, as criticism of the force mounted, Wright oversaw the operation, which included changing 164 junior officers' statements and briefing false stories to the media, to avoid responsibility and blame the supporters themselves.

Chris Kitchen, the general secretary of the National Union of Mineworkers, who was at Orgreave as a 17-year-old on strike, said the miners have ever since maintained they were the victims of police malpractice including fabricating evidence to secure convictions.

"Most of the men were acquitted but those who accepted being bound over had a criminal record for the rest of their lives," he said. "They had to return to an industry which was being shut down, then look for different work, with that on their record.

"We want an investigation into what the South Yorkshire police, and other forces, did during the strike, now we have seen the proven malpractice following Hillsborough exposed for what it was."

Kitchen said he will ask the NUM's national executive committee to consider at its meeting next month formally asking the IPCC and the DPP, Keir Starmer, to widen their current investigations into Hillsborough to include the South Yorkshire police conduct during the miners' strike.

After the detailed exposure of the shocking truth about Hillsborough, based on the South Yorkshire police's own records of their conduct, the miners may move closer, almost 30 years on, to the truth of what was done to them, by the same force, under the regime of the same chief constable.